The latest research proves that wider tyres are actually faster than thinner ones for real world road riding. They’re more comfortable and less puncture prone too, but which are the best bigger 25mm tyres for your riding needs?
By fatter tyres what we’re talking about are 25mm rather than 23mm wide tyres. 28mm tyres can actually roll even faster on rough roads but very few aero or road race frames have enough clearance for these tyres to fit. Check our verified measurements rather than believing tyre labels too as actual widths of “25s” can vary from 22-26mm.
As the carcass and design of tyres changes and rims get wider tyres are generally less round than they used to be. That means most 25mm tyres aren’t that tall and some are really shallow despite being broad. Extra depth generally means more protection from impacts and easier rolling comfort too so it’s worth checking stats to see which tyres really are larger.
The carcass is the body of the tyre formed by overlapping layers of cloth. As a general rule the finer the base cloth the more supple and flexible the tyre. The ability to deform easily around bumps and imperfections in the road surface gives a smoother, better gripping and more speed sustaining ride too.
The rubber used in the tread over the top of the carcass also has a big effect on performance. Harder compounds generally roll a bit faster and last longer but they don’t grip as well and if they’re too hard to flex easily they can actually be slower. Softer compounds grip better but their stickiness can slow you down and they wear out quickly. That’s why a lot of tyres use a harder centre for speed and softer shoulders for cornering grip.
Most tyres have some sort of protective layer under the tread to try and stop thorns, glass and other pointy debris getting to your inner tube and puncturing it. The thickness, width and effectiveness of these layers varies dramatically though as does their ride quality. Some tyres also have protective layers on the side walls to minimise the danger of cuts and splits from scuffs and bumps which is useful for commuting or rougher road use.
They’re still not common on the road, but by making the tyre and rim airtight and then adding a liquid sealant (that cures instantly if anything punctures a hole in the tyre) you can do without an inner tube. This improves pinch and pointy puncture proofing and can theoretically give a more supple feel. Only a few tubeless tyres actually deliver on that promise though and tight fit, wooden feel and slow leaks are regular problems on less sorted tubeless tyres.